zshrc to show timing of last command

timer.sh

# High-precision timer using epoch nanoseconds
function preexec() {
  TIMER=$(gdate +%s%3N 2>/dev/null || date +%s%3N)
  LAST_COMMAND="$1"
}

function precmd() {
  if [[ -n "$TIMER" && -n "$LAST_COMMAND" ]]; then
    NOW=$(gdate +%s%3N 2>/dev/null || date +%s%3N)
    DURATION=$((NOW - TIMER))
    if (( DURATION > 1 )); then
      echo "\033[2m⏱️  ${DURATION} ms\033[0m"
    fi
  fi
  unset LAST_COMMAND
}